1. Field of the Invention
The invention relates to an image processing apparatus, image processing method and program and, more particularly, to an image processing apparatus, image processing method and program that give low calculation cost and that are able to extract a simply usable feature descriptor from an image.
2. Description of the Related Art
An image recognition technique for recognizing a target object in an image is an image processing technique having a wide range of application, and an image recognition method has been widely researched. In an existing art, there are a technique for detecting the position of a feature point in an image and a technique for detecting the feature descriptor at the position of the detected feature point as a technique related to image recognition.
For example, detecting methods, such as a “Harris corner detector”, a “SUSAN corner detector” and a “KLT corner detector”, are proposed as the technique for detecting the position of a feature point (see, for example, C. Harris and M. Stephens, “A combined corner and edge detector,” Proc. 4th Alvey Vision Conf., pp. 147-151, Manchester, U.K., August 1988, the specification of United Kingdom Patent No. GB2272285, and C. Tomasi and T. Kanade, “Detection and Tracking of Point Features” Technical Report CMU-CS-91-132).
In addition, detecting methods using “Steerable filters” or “Complex filters” and detecting methods, such as “SIFT descriptor” and “PCA-SIFT”, are proposed as the technique for detecting a feature descriptor (see, for example, W. Freeman and E. Adelson, “The Design and Use of Steerable Filters,” IEEE Trans. Pattern Analysis and Machine Intelligence, vol. 13, no. 9, pp. 891-906, September 1991., F. Schaffalitzky and A. Zisserman, “Multi-View Matching for Unordered Image Sets,” Proc. Seventh European Conf. Computer Vision, pp. 414-431, 2002., the specification of U.S. Pat. No. 6,711,293, and Y. Ke and R. Sukthankar, “PCA-SIFT: A More Distinctive Representation for Local Image Descriptors”, Computer Vision and Pattern Recognition, 2004).